#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/Support/ValueHandle.h"
#include "llvm/Instructions.h"
#include "llvm/Support/PatternMatch.h"
using namespace llvm;
using namespace llvm::PatternMatch;
-/// SimplifyAndInst - Given operands for an And, see if we can
+/// SimplifyAddInst - Given operands for an Add, see if we can
/// fold the result. If not, this returns null.
-Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1,
+Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const TargetData *TD) {
+ if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
+ if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
+ Constant *Ops[] = { CLHS, CRHS };
+ return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(),
+ Ops, 2, TD);
+ }
+
+ // Canonicalize the constant to the RHS.
+ std::swap(Op0, Op1);
+ }
+
+ if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
+ // X + undef -> undef
+ if (isa<UndefValue>(Op1C))
+ return Op1C;
+
+ // X + 0 --> X
+ if (Op1C->isNullValue())
+ return Op0;
+ }
+
+ // FIXME: Could pull several more out of instcombine.
+ return 0;
+}
+
+/// SimplifyAndInst - Given operands for an And, see if we can
+/// fold the result. If not, this returns null.
+Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD) {
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
Constant *Ops[] = { CLHS, CRHS };
// A & ~A = ~A & A = 0
Value *A, *B;
- if (match(Op0, m_Not(m_Value(A)) && A == Op1) ||
- match(Op1, m_Not(m_Value(A)) && A == Op0))
+ if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
+ (match(Op1, m_Not(m_Value(A))) && A == Op0))
return Constant::getNullValue(Op0->getType());
// (A | ?) & A = A
/// SimplifyOrInst - Given operands for an Or, see if we can
/// fold the result. If not, this returns null.
-Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1,
- const TargetData *TD) {
+Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD) {
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
Constant *Ops[] = { CLHS, CRHS };
// A | ~A = ~A | A = -1
Value *A, *B;
- if (match(Op0, m_Not(m_Value(A)) && A == Op1) ||
- match(Op1, m_Not(m_Value(A)) && A == Op0))
+ if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
+ (match(Op1, m_Not(m_Value(A))) && A == Op0))
return Constant::getAllOnesValue(Op0->getType());
// (A & ?) | A = A
}
-
-
static const Type *GetCompareTy(Value *Op) {
return CmpInst::makeCmpResultType(Op->getType());
}
return 0;
}
+/// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
+/// fold the result. If not, this returns null.
+Value *llvm::SimplifyGEPInst(Value *const *Ops, unsigned NumOps,
+ const TargetData *TD) {
+ // getelementptr P -> P.
+ if (NumOps == 1)
+ return Ops[0];
+
+ // TODO.
+ //if (isa<UndefValue>(Ops[0]))
+ // return UndefValue::get(GEP.getType());
+
+ // getelementptr P, 0 -> P.
+ if (NumOps == 2)
+ if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
+ if (C->isZero())
+ return Ops[0];
+
+ // Check to see if this is constant foldable.
+ for (unsigned i = 0; i != NumOps; ++i)
+ if (!isa<Constant>(Ops[i]))
+ return 0;
+
+ return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]),
+ (Constant *const*)Ops+1, NumOps-1);
+}
+
+
//=== Helper functions for higher up the class hierarchy.
/// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
switch (I->getOpcode()) {
default:
return ConstantFoldInstruction(I, TD);
+ case Instruction::Add:
+ return SimplifyAddInst(I->getOperand(0), I->getOperand(1),
+ cast<BinaryOperator>(I)->hasNoSignedWrap(),
+ cast<BinaryOperator>(I)->hasNoUnsignedWrap(), TD);
case Instruction::And:
return SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD);
case Instruction::Or:
case Instruction::FCmp:
return SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
I->getOperand(0), I->getOperand(1), TD);
+ case Instruction::GetElementPtr: {
+ SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
+ return SimplifyGEPInst(&Ops[0], Ops.size(), TD);
+ }
+ }
+}
+
+/// ReplaceAndSimplifyAllUses - Perform From->replaceAllUsesWith(To) and then
+/// delete the From instruction. In addition to a basic RAUW, this does a
+/// recursive simplification of the newly formed instructions. This catches
+/// things where one simplification exposes other opportunities. This only
+/// simplifies and deletes scalar operations, it does not change the CFG.
+///
+void llvm::ReplaceAndSimplifyAllUses(Instruction *From, Value *To,
+ const TargetData *TD) {
+ assert(From != To && "ReplaceAndSimplifyAllUses(X,X) is not valid!");
+
+ // FromHandle - This keeps a weakvh on the from value so that we can know if
+ // it gets deleted out from under us in a recursive simplification.
+ WeakVH FromHandle(From);
+
+ while (!From->use_empty()) {
+ // Update the instruction to use the new value.
+ Use &U = From->use_begin().getUse();
+ Instruction *User = cast<Instruction>(U.getUser());
+ U = To;
+
+ // See if we can simplify it.
+ if (Value *V = SimplifyInstruction(User, TD)) {
+ // Recursively simplify this.
+ ReplaceAndSimplifyAllUses(User, V, TD);
+
+ // If the recursive simplification ended up revisiting and deleting 'From'
+ // then we're done.
+ if (FromHandle == 0)
+ return;
+ }
}
+ From->eraseFromParent();
}
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